How to Use the Stream-Finder
Months Ahead, A Few Days Ahead, Hours Ahead
These directions for the StreamFinder are to figure out which streams will be running months in advance (in case you’ve promised your local canoe club to lead a trip), in the near future (like, a week), or within hours. The StreamFinder, was meant, back in 2014 as an improvement on the popular American Whitewater website, here in the Washington-Baltimore area. Now AW has pulled up its socks and is almost as good.
On AW, those streams in spate are nicely highlighted in green, those too low in a pinky-brown with links and all the rest. While this works, it has several problems which this guide, also web-linked, seeks to correct or avoid. While AW links each stream to but one USGS gauge, this guide sometimes uses on-line gauges on several creeks – the Lost uses 5 gauges, and Gaither Gorge uses 3. Too often AW gives the USGS gauge’s measures in feet, whose meaning is obscure to newbies and paddlers from out-of-area, whereas this guide uses the universally comprehensible and comparable cfs (cubic feet per second). Reflecting the paddling community’s ancient custom, stage readings are retained for sections like Little Falls, the Staircase, and the James Fall Line. The SF groups the streams by region and by watershed to speed your selection.
The SF tables put you in charge as you select your stream. Put StreamFinder on your desktop.
Now for the steps:
Long before the Trip
1 – Set up your own USGS Water Alerts – “In time of peace, prepare for war.” Before the rains fall, get USGS to tell you when your favorite streams become navigable. Go on the USGS site http://waterdata.usgs.gov/nwis/rt and on the particular gauge page you want – look on the right and below the gauge table for the Water Alert link. Enter the minimum cfs you need to run the stream. Some gauges ask you to enter your minimum reading not in cfs, but in feet. If so, you must go to the two-column table for that gauge and by looking backwards to obtain that equivalent for your desired minimum cfs figure. I have 17 ready to ping my e-mail telling that x, y, or z stream has just exceeded my designated minimum.
2 – Will I Likely Have Enough Water on D-Day? Check the Average Volume of your stream on your desired date in USGS Real Time Stream Flow (see #5, below) shown by the string of small yellow triangles arrayed along with the blue line showing the hourly/daily discharge (volume) passing the particular gauge. Say you want to lead a group down Passage Creek Gorge in mid-August. In SF click on the relevant gauge (here: Buckton), and the yellow triangles say that average flow then is just 14 cfs – far too low, as the SF also shows [150 cfs] as the minimum for that trip. And, remember, in most cases, you’ll have more fun at volumes twice the minimum or more.
A Few Days before the Trip
3 – Look at the Quantitative Precipitation Forecast (QPF) for 2-7 days ahead: on StreamFinder click Predicting Water Levels – Weather, Section 1. These maps with the green and blue amoeba blobs tell when and how much the rains will be.
4 – Check the Local Forecast – On the left of the QPF page – type in the nearest City and State, and up come nine little pictures of weather happening – under which is your “Detailed Forecast.” Hourly Weather Graph - rich with wind, temperature, precipitation, relative humidity, chance of precipitation, and even wind chill data - by the hour. Pass your stylus over the chart to the time of day you want, and you will see the values also displayed below the several charts. On the chart two days worth of data are displayed – for farther into the future, above and to the left of the charts - at “48-Hour Period Starting:” click on the “Submit” button. Or at the top right, it offers tabs saying “Forward 2 Days” and “Back 2 Days.” Go one table below this for the vertical green bars predicting rainfall by the hour – and summing up how many inches may fall in a certain period. Highly useful. Over on the right is the Radio & Satellite Images - with the incoming weather map with the former LWX or Sterling Loop.
Just before the Trip
5 – USGS Real Time Stream Flow No more predicting, we’re ready to find out what’s running right now. So return to the StreamFinder and go to the Whitewater Gauge Tables by clicking on the name of the State where your hoped-for brook dwells. When the tables appear, click once again on the STATE NAME in the table title to get the polka dot USGS WaterWatch Map with the blue, green, etc. dots for the gauges telling relative volumes on that date. They indicate, but do not promise, that there is enough water in that creek. Expand the map. The lay of the black or dark blue dots indicates where the chances of water are best (or where to stay away from – and wait until tomorrow). Click on the dots for precise info.
6 – Using the StreamFinder Tables These are the heart of the SF. Go back to the watershed table in which you’re interested. There, click on the gauge that relates to your stream. Be guided by the square-mile figures as to where to look for a likely brook. With more rain falling or snow melting outside, look at the smaller creeks and upstream on any particular one. Compare the real-time gauge reading on USGS with the “Min CFS” (cubic feet per second) shown in the SF’s next column telling the lowest volume at which the streams can be run. On that graph, see how swiftly the water is diminishing and figure if you can get there in time (incl. setting shuttle). Some streams (in Baltimore: Gwynns Falls, Jones Falls, and Herring Creek; around DC: Pohick Creek, Cabin John Creek, Accotink, and Pimmit Run) often must be run in the rain. So, in the last column there are links to various rainfall gauges – see also Predicting Water Levels – Weather, Section 5.
The Streams, Arrayed by Size (and so, by Season)
Choosing by Stream Size – Here, in descending order of likelihood that there will be sufficient water, are the choices:
A – Largest Streams As the rains taper off at season’s end, for whitewater there are only four major games in town – and for two of them you must drive far: First is the Lower Potomac (11,385 mi²), with Little Falls (Cl. III), the Chutes, Anglers to Lock 10 (Cl. II), Violettes Lock Loop (Cl. II), and Mather Gorge, (Cl. II+) – which are always up. Also the James Fall Line at Richmond (6,753 mi², Cl. III) and the Lower Yough (1,029 mi², Cl. III+). Flat sections of the South Branch Shenandoah – Foltz Mill to Luray/VA 211 – and below. And at season’s end – below the N & S Fork confluence at Front Royal – US 50 to Lowes Landing and farther downstream.
B - Mid-Sized Rivers are next: – Rappahannock Fall Line at Fredericksburg (1,600 mi²), the Potomac Needles (6,311 mi², Cl. II) and Shenandoah Staircase (3,041 mi², Cl. II (III) at Harpers Ferry, the South Fork Shenandoah, Brandywine (Pa+Del) (300 mi², Cl. II+), – Patapsco (dam influenced – 285 mi², Cl. II+), Antietam (200 mi², Cl. II), Codorus (266 mi², Cl. II+), Casselmans (382 mi², Cl. II+), Maury (~300 mi², Cl. III+), Rappahannock at Kellys Ford (619 mi², Cl. II+), Goose Creek (340 mi², Cl II+), Potomac So Fork, So Br (Moorefield Canyon) 100 mi², Cl II+), Hopeville Canyon (No Fk, So Br, 304 mi², Cl. III), mid-Cacapon (330 mi², Cl II+), Brandywine, Pa/Del (300 mi², Cl. II+)
C - Large Creeks – Muddy Ck, Pa (138 mi², Cl. II+), Lost R (177 mi², Cl. III), Cedar Creek (56/100 mi², Cl. II), Passage Creek (83 mi², Cl. II+), Marsh Ck, Pa (75 mi², Cl. II+), Stony Ck, Va (75 mi², Cl. II+), Middle Hughes (43 mi², Cl. II), Thornton R. (35 mi², Cl. II), Tye (30 mi², Cl. III)
D – Small Creeks – (4-50 mi²) and any urban creek – These “flashy” brooks run out of water fast, so you must be on your toes – within three hours of a rainfall in some cases. Once you start looking for these, you’ll be sadly impressed at how often rain seems to fall at 6-9 PM – peaks around midnight – and is gone by morning. If you want to bag a rivulet, you must be ready to ride at crack of dawn. Here are some: Rock Creek (67 mi², Cl. III), Little Patuxent (38 mi², Cl. III), Accotink Ck (37 mi², Cl. II), Pohick Ck (21 mi², Cl. II+), Cabin John Ck (18 mi², Cl. III). More lurk up on the Fall Line in Baltimore & Harford County MD.
E - Dam Controlled Rivers – Upper Gunpowder Falls (81 mi²), can flow unexpectedly in August and September, the mid Patuxent has a fairly constant flow (79 mi², 80 cfs, Cl. 1) at Brighton Dam, and the Savage in Garrett Co, MD at natural flow; Seneca Ck, Montgomery Co. (101 mi², Cl. I), the Stonycreek, Pa (450 mi², Cl. III), the North Anna (~450 mi², Cl III), the Lower Gunpowder Falls - GPF (340 mi², Cl. III) and, again the Lower Yough (1,029 mi², Cl. III+). Bloomington at a non-release 350 cfs is possible.
River Temperatures – As the season winds down, these become of vital interest as temps drop below 50 degrees. Most streams lack thermometers, but look at Little Falls (Potomac), Cartersville (James), Friendsville & Confluence (Yough), Chadds Ford (Brandywine), and Parkton (Upper Gunpowder Falls)
Alf Cooley alfcooley@gmail.com - 21 Jan 2015, 18 Feb 2022, Please comment & correct